Multipulse regimes of excitation of optical superradiance due to a two-photon transition

Multimode triggered optical superradiance due to a two-photon transition is theoretically studied. Kinetic equations are derived for the dynamics of cooperative development of coherence and population inversion of optical centers interacting with each other through a common field of emitted photons. Various regimes of triggering of optical superradiance due to a two-photon transition are considered. The possibility of creating a quantum photomultiplier on the basis of the triggered optical superradiance is discussed.     

Optical superradiance on cooperative transitions in metamaterials

The possibility of observing collective spontaneous emission upon a cooperative transition in an ensemble of interacting optical center pairs embedded in a metamaterial is investigated. It is shown that when the effective refractive index tends to zero, the relaxation rate of excited atomic states substantially decreases, allowing us to observe collective effects on weaker cooperative transitions.     

Effect of Metal Complex Binding on the Properties of Polymethyl Methacrylate

Coordination binding of polymethyl methacrylate with copper(II) ions was studied by IR spectroscopy and viscometry.     

Cooperative superfluorescence in nanoclusters

The features of superfluorescence (SF) in nanoclusters, which consist of a few neighboring particles interacting with each other by exchange or/and electrostatic forces, are investigated theoretically. It is shown that there are two types of cooperatively SF depending on the ratio between the linear size of a nanocluster and the cooperative interaction range. Experiments on cooperative luminescence in Ytterbium-doped silica fibers are analyzed. It is shown that the intensity of cooperative SF in such a system should be proportional to the fourth degree of Ytterbium concentration.     

Binding energies of hypernuclei and ΛN interaction

A central ΛN potential V _ΛN that describes, in the limits of experimental errors, the binding energies of three-, four-, and five-particle ground and excited states of hypernuclei, as well as energy and angular dependence of Λp scattering cross sections, is found on the basis of a conjoint analysis of binding energies of 1s-shell hypernuclei and Λp scattering. The reliability and accuracy of three-, four-, and five-particle calculations of hypernuclei and related nuclear systems are assured by the estimation of, an upper, as well as a lower bound of energy. In the framework of the model Λ+core, V _ΛN agrees with binding energies of heavy hypernuclei.     

Binding energies of hypernuclei and ΛN interaction

A central ΛN potential V _ΛN is found on the basis of an analysis of the binding energies of 1s-shell hypernuclei and Λp scattering. Within the exprerimental errors, this potential makes it possible to reproduce the binding energies of three-, four-, and five-particle ground and excited states of hypernuclei and the angular and energy dependences of the cross sections for Λp scattering. The accuracy and reliability of the calculation of three-, four-, and five-particle hypernuclear and the respective nuclear systems is ensured by determining both upper and lower bounds on the energy. Within the Λ plus core model, the potential V _ΛN is matched with binding energies of heavy hypernuclei.     

Formation of photonic echo signals in the presents of a strong concentration quenching effect

The connection between the photonic echo formation in crystals doped by rare-earth elements and the concentration effects was studied. The application of optical echo spectroscopy in studies of garnet crystals with a high content of thulium impurity was demonstrated. By the example of activated crystals of ruby and lanthanum trifluoride, the spectral transformation of the photonic echo signals was analyzed in the present of the concentration quenching effect.     

Generation of narrow-band correlated photon pairs by spontaneous down conversion in a cavity

The problem of generating a narrow-band biphoton field during spontaneous parametric down conversion of light in a quadratic nonlinear medium in a cavity is discussed. It is shown that, in the case of double resonance (for signal and idle fields), the form of the single-photon wave packet is biexponential and has a half-width determined by the photon life time in the cavity. An experiment is carried out on the generation of narrow-band biphotons in a crystal of lithium iodine with I-type matching in a frequency degenerate collinear regime. The second-order correlation function of the cavity-enhanced biphotons is measured using the electric nanosecond time delay line.